A colloidal damper described in each of the following Patent Literatures uses a colloidal solution in which are mixed a fluid and porous bodies such as hydrophobized porous silica gel. In the colloidal solution, the fluid repeatedly flows in and flows out of the pores of each porous body under an action of surface tension, whereby an energy applied from an exterior is dissipated. The colloidal damper has characteristics that conventional hydraulic dampers do not have. For instance, in the colloidal damper, the energy dissipation amount is equal to an amount that depends on an amplitude of a vibration. Thus, it is expected that the colloidal damper will be applied to various fields.